London (CNN) -- Coptic churches around Europe are expressing fears for their safety following a New Year's Day attack on a church in Egypt that had been listed on an Islamist website.

The same site, which is affiliated with the al Qaeda terror network, listed 16 Coptic churches in Europe, including four in France and three each in England and Germany.

Germany's Federal Office for Criminal Investigations said it has notified state authorities of a general terrorist threat against Coptic Christians living in Germany. A spokeswoman said the office issued the notification after the threats were discovered on the site.

"It's up to the state authorities to decide how they react to such a threat," said spokeswoman Barbara Huebner, without going into detail about the threat.

France has heightened security around 19 Coptic churches ahead of January 7, the date when Coptic communities celebrate Christmas, a spokesman from the French National Police said.

French anti-terror police have begun an investigation into the threats made against Coptic churches in their country after a Coptic priest near Paris made a formal complaint, a spokeswoman for the Paris police said.

The priest, Girguis Lucas, is with the Coptic Church of St. Marie and St. Marc on the capital's outskirts and confirmed he made the complaint.

The Coptic Church in Britain is also concerned about the threat, said Father Shenouda Shenouda, a representative of the Coptic Orthodox Church Centre in England.

"The Coptic Church in the UK has been threatened together with the Coptic Churches all around Europe, America, Australia, and several Coptic churches in Egypt," he told CNN. "We haven't received a direct threat, but through a website."

Bishop Angaelos, the general bishop of the Coptic Orthodox Church in Britain, said church officials have been in touch with London's Metropolitan Police and have made them aware of the threats on the site, though the police said they had not received reports of any threats.

A police spokesman told CNN authorities are aware of the events in Egypt "and of threatening comments against the Coptic community worldwide made on a website.

"The MPS is continually monitoring any community tensions in London, and over the coming days officers will be liaising with Coptic and other community members to reassure them and give crime prevention and safety advice," the spokesman said. "At this stage there is no specific information relating to threats against specific Coptic churches in the Metropolitan Police area."

Michele Riad, a spokesman for Coptic Bishop Anba Damian in Germany, said the church there is taking the threats seriously. He said the church is in close touch with local authorities and has designated a security liaison to discuss police measures for the Christmas celebrations.

Damian has decided to shorten the celebrations in part because of the threat, but also to mourn those killed in the January 1 attack, Riad said.

"We are not scared, but we are very concerned," he told CNN.

At least 21 people were killed and 97 others wounded in the blast that happened shortly after Egypt rang in the new year, as Coptic Christians were attending services at the Church of the Two Saints in Alexandria, Egypt.

Copts are adherents to an Egyptian sect of Christianity. They make up about 9% of the population in Egypt, which is about 90% Muslim.

A suicide bomber was believed to be behind the blast, which left the church littered with broken glass and debris and the walls spattered with blood.

The Alexandria church was listed on the same website that made the threat against the European churches. Twelve other Coptic churches in Egypt were also named, along with Coptic churches in Switzerland, the Netherlands, Sweden, Austria, Denmark, the United States and Australia.

The list first appeared December 2 on the Shumukh al Islam website, a radical Islamist site affiliated with al Qaeda. The European churches voiced alarm after the church in Alexandria was attacked.

The person who posted the list online urged followers to "blow up the churches during the Christmas celebration since it is the best time, where these churches are crowded."

The list ends with a link to a manual on how to make a bomb.

The Anglican bishop of Egypt said Tuesday that all Anglican and Episcopal churches in the country are strengthening their security measures following the Alexandria bombing.

The Most Rev. Dr. Mouneer Hanna Anis said he was cooperating with a request from the Egyptian security services in enacting the measures, which involve creating security barriers and using security cameras.

Meanwhile, Saudi Arabia's grand mufti was the latest world leader to condemn the bombing, according to the official Saudi Press Agency. The Alexandria bombing, he said in a speech Monday, is condemned by Saudi Arabia and the whole world, and neither serves nor relates to Islam, according to SPA.

"These continuing events are planned by the enemies of Islam to weaken Muslims and to provoke non-Muslims to target Muslims indiscriminately," the grand mufti said. "Destroying the Nation of Islam is their ultimate goal."